How to Reduce Shrinkage in PP Plastic

PP, or polypropylene, is a material known for its low density, high impact resistance, heat resistance, chemical resistance, and low cost. However, PP has a high shrinkage rate, leading to significant dimensional shrinkage and deformation after injection molding. Therefore, reducing shrinkage is a key modification direction for PP plastic. Next, we will briefly introduce how PP plastic can reduce shrinkage.

1. Adding glass fiber fillers: Incorporating different concentrations of glass fiber into PP resin can significantly reduce its shrinkage rate. For example, when the glass fiber content exceeds 30%, the molding shrinkage rate of modified PP material can decrease from 1.8% to 0.5%;

2. Adding inorganic fillers: Inorganic fillers such as talc, calcium carbonate, and barium sulfate can effectively reduce the shrinkage rate of PP. These fillers alter the structural state of PP, acting as nucleating agents to prevent the formation of large spherulites, thereby influencing the crystallinity and shrinkage rate of PP;

3. Adding other non-crystalline resins, such as LDPE, HDPE, PS, ABS, PMMA, PC, etc., can disrupt PP crystallization and reduce shrinkage;

4. Blending elastomers: Adding elastomers such as POE, EPDM, SBS, etc., can reduce PP shrinkage. Mineral filler and elastomer co-mixing: Using inorganic fillers and elastomers in a co-mixing process in PP can more effectively reduce shrinkage;

5. Adjusting processing parameters: Experienced injection molding engineers can adjust injection molding parameters such as temperature, pressure, and cooling rate.

Through the above methods, the shrinkage rate of PP plastic can be effectively reduced, improving the dimensional stability and consistency of the product.

QINGDAO PRIME UNION TRADE has been acting as the agent of Mitsubishi raw materials since 2002. It has offices in Zibo and Qingdao, with sales offices and warehouses. The raw materials are in sufficient stock and can be shipped at any time. The company is registered in Qingdao Free Trade Zone and has the right to import and export. It can carry out re-export trade, customs manual trade --customs supervision, and general trade in US dollars in the zone. At the same time, our brother company Qingdao Meitai Plastic is a modification plant with 16 years of experience, which can provide one-stop services for plastic modification, dyeing, and injection molding. If you need our products, please feel free to call us or leave a message/online communication.